Many man-hours are expended in the collection of litter and other debris from large community areas such as along streets and highways, parks, playgrounds, along beach areas and open commercial areas. Because of the difficulty of designing a machine which will collect the various types and sizes of litter and operate over various types of ground surfaces, manual retrieval has often been relied on. Moreover, manual retrieval methods are slow and many times are ineffective, particularly where large areas must be patrolled.
Machines have been designed to supplement or replace the need for manual retrieval of litter. An effective apparatus for litter retrieval is disclosed in U.S. Pat. No. 3,807,154, to the inventor of the present invention, issued Apr. 30, 1974. This patent discloses the use of a towed apparatus having a rotatable drum which is rotated upon ground engagement. A plurality of flexible fingers extends radially from the drum and has a particular configuration for receiving bottles and cans therebetween during the movement of the apparatus along the ground surface. Bottles, cans and similar objects engaged by the drum and fingers are collected in a hopper after being stripped from the fingers.
Although the device described in U.S. Pat. No. 3,807,154 is capable of retrieving some objects, such as bottles and cans, the effectiveness of the device has been less than completely satisfactory for other types of litter. Where the particular object cannot be grabbed between the resilient fingers extending from the drum, then the apparatus may fail to collect the debris.
It is critical that an apparatus for collecting litter be able to retrieve bottles, cans and objects having arcuate outer surfaces of a form retaining nature, as well as simultaneously collecting materials such as paper, and various containers made thereof, textile materials and other flat or semiflat objects. Thus, the need has arisen for a device which can simultaneously collect both bottles and cans, which make up a large portion of the litter in large public and private areas, as well as other debris of differing shapes and materials.
Prior apparatus with respect to these types of devices have also failed to properly disclose a means for supporting the weight of the drum and finger assembly without sustaining damage to the fingers. Further, such support must not permit an excessive "dead space" which is not engaged by the fingers where the device encounters irregular terrain.